Well, I have one right now that gets along with everything in my tank, a very nice fish. Hes a decent size, about 3 inches or so, but I've heard when they get bigger they get more aggressive. I used to have one that was terrible, even in a 75 gallon tank, he would chase everything :mad2 , then I came home one day and found him behind the tank, stiff as a board :sad , I felt so bad, he found the smallest space and must have jumped just right! I guess it depends on the fish, but in general, they're very territorial! I guess you could always try one, with the possibility of a return to the LFS. I would not put them with very shy or slow moving fish. Mine never hurt the other fish, just chased them relentlessly. Also a BIG tank and lots of hiding space would help.
Sorry, I had no specific suggestions! Good luck